Attachment for bulldozer moldboards



July 28, 1959 C. H. RABY ATTACHMENT FOR BULLDOZER MOLDBOARDS Filed Oct. 9, 1956 INVENTOR I hf RAB) CLAUDE ATTORNEYS United States 2,896,343 Patented July 28, 1959 iiltiice 2,896,343 ATTACI-IlVIENT FOR BULLDOZEE MOLDEOARDS Claude H. Raby, Knoxville, Tenn.

Application October 9, 1956, Serial No. 614,910

4 Claims. (Cl. 37-98) This invention relates to an attachment for bulldozer moldboards, and more particularly to an attachment adapted to be applied to a bulldozer moldboard for the purpose of forming a footing trench.

In the construction of buildings, it is the usual practice to form a trench around at least a portion of the periphery of the building, and to form in this trench a footing of concrete or other material, which footing serves as a foundation for the building structure. In some soils the formation of a footing trench is an extremely difficult task. Moreover, the expense involved in forming the footing trench in hard earth by manual labor is often excessive.

It is an object of this invention to provide an attachment for the moldboard of a bulldozer so that the formation of the footing trench may be accomplished by utilizing the power of the bulldozer.

Another object of the invention is to provide a moldboard attachment which. can be applied quickly and easily to moldboards of various sizes and shapes, so that it may be usedin connection with many different bulldozers,

Still another object of the invention is to provide a moldboard attachment of a construction such that it will be economical to manufacture, and durable and efficient under service conditions.

The foregoing objects are obtained according to one embodiment of this invention by. the provision of a footing-trencher attachment which includes a rugged frame having a pair of upwardly opening, laterally spaced notches on its rear surface for the reception of the lower end of the moldboard of a bulldozer, and having a vertically reciprocable clamp for engaging the upper end of the moldboard. The clamp preferably includes a pair of laterally spaced moldboard gripping members, each of which is formed so that its lower surface presents two angularly related planes in position to engage, respectively, the front and rear edges of the top of the moldboard of the bulldozer, .and the clamp is adapted to be manipulated by the adjustment of a wing nut upon an elongated screw threaded member carried by the frame on the attachment. The lower end of the frame is provided with a removable trench-forming blade of the desired shape.

The construction of the attachment of this invention is such that it may be applied, without modification and without the use of tools, to the moldboard of many of the bulldozers nowin general use. Its novel configuration and its distinctive facility for adjustment over wide ranges make it a truly universal attachment.

Other objects and advantages of. the invention will become apparent upon a consideration of the following detailed description of the embodiment illustrated in the accompanying drawings, in which:

Fig. l is a perspective view of the attachment as applied to a bulldozer moldboard of typical shape;

Fig. 2 is a front elevational view of the attachment shown in Fig. 1; and

Fig. 3 is a vertical cross sectional view taken along the line 33 in Fig. 2.

In Fig. 1, the numeral 2 has been applied to the moldboard of a bulldozer. It will be understood that the particular shape of this moldboard may vary somewhat in practice. There are many different manufacturers of bulldozers, and the moldboards of different manufacturers differ slightly in shape from each other. Also, the moldboards of the popular bulldozers vary substantially in their dimensions. For example, a bulldozer intended for heavy work may have a moldboard which is much taller than the moldboard of a bulldozer intended for light work. The attachment of this inven tion is so designed that it may fit all of these different moldboards.

In the interest of clarity, the bulldozer itself and its connections to the moldboard 2 have been omitted fromthe drawings. Thesefeatures may be entirely conventional, and they form no part of the present invention.

The attachment of this invention includes a frame des ignated generally by the numeral 4. This frame includes a rigid backing plate 6 to which a generally rectangular, trench-forming blade 8 is detachably secured by means of bolts 10, or other suitable fasteners. The detachable connection between the blade 8 and the frame 4 is important. All footing trenches are not the same size, and blades wear out after a period of use. The attachment of this invention permits a blade to be changed easily when this is required.

Welded to the rear. face of the backing plate 6 are a pair of spaced apart rigid members 12 and 14. Each of the members 12. and 14" has an inclined upper face which forms, with the rear face of the backing plate 6, an upwardly opening notch for the reception of the lower end of the moldboard 2 of the bulldozer. As will be evident from Fig. 1, these notches are laterally spaced apart so that the positional relationship between the moldboard 2 and the frame 4 is definitely established when the lower end of the moldboard 2 is inserted into the notches.

The front face of the backing plate 6 has welded thereon a pair of laterally spaced rigid support members 16 and 18, and these members in turn carry spaced uprights 2d and 22 welded to their upper surfaces, respectively. Additional rigidity in the construction is achieved by braces 24 extending between and welded to the uprights 20 and 22.

The upper end of the moldboard 2' of the bulldozer is engaged by a clamp 26 slidably mounted upon the uprights 20 and 22. The clamp 26 includes a pair of identical laterally spaced moldboard gripping members or hooks 28 and 30. As best shown in Fig. 1, the shapes of the hooks 28 and 30 issuchthat these elements may firmly grip moldboards having a substantial range of widths at their upper ends. This advantageous relationship is. achievedby shaping the lower surface of each of the hooks to provide. two angularly related planes 32 and 34. With this configuration, the planes 32 and 34 may bear respectively upon the front and rear edges of the top end of theimoldboard 2, as shown in Fig. 1-, and the distance. between the bearing areas'may vary without any physical alterations in the structure. A thicker moldboard 2 will contact thetwo planes 32 and 34 at points further away: from thejuncthre of" these planes than will a thinner moldboardf blade;

The presence of the two laterally spaced gripping members 28 and 30'" serves to prevent twisting of the attachment in the plane of the moldboard 2. This has particular significance in connection with a footingtrencher because footing trenches frequently must be formed in very hard sub-soil and the loads imposed upon the trencher are usually large.

The clamp 26 may be urged into clamping relationship with respect to the upper end of the moldboard 2 by the manipulation of a wing nut 36 carried by an elongated threaded member or bolt 38, the lower end of which is rigidly attached to a bifurcated element 40. The lower ends of the bifurcated element 40 are apartured for the reception of a pin 42 which passes also through a selected one of a series of holes 44 in a vertical member or plate 46 welded at its lower end to the braces 24. This pin 42 may be held in position by friction or it may be fixed in position by any easily removable means such as cotter keys passing through the ends thereof in the conventional manner.

It will be seen that the structure just described has the potential for vertical adjustment over the substantial range required by variations in the heights of the moldboards commonly used on bulldozers. Most of the situations ene countered in practice may be handled simply by varying the position of the wing nut 36 upon the screw threaded member 38. Since the screw threaded member 38 is rather long this will lead to a positioning of the hook members 28 and 30 at a wide variety of heights. If additional adjustment is necessary, this may be accomplished by relocating the pin 42 with respect to the holes 44 in the plate 46.

The manner of using the invention now should be apparent. The attachment of this invention is placed in an upright position upon the ground in front of the raised moldboard 2 of a bulldozer; the moldboard 2 is lowered to position its lower end in the notches formed by the backing plate 6 and the members 1.2 and 14; the

frame 4 is swung rearwardly to bring the gripping members 28 and 30 into position over the top end of the mold board 2; and then the wing nut 36 is manipulated manually to clamp the parts together. It does not matter where along the length of the moldboard the attachment is located.

The bulldozer then is driven along the desired path, and the blade 8 of the trenching attachment forms a footing trench of the necessary shape. In some instances it is necessary to make several passes along the desired path in order to produce a trench of the proper depth.

Although a specific embodiment of the invention has been described in detail, various modifications and variations will be apparent to persons skilled in the art. Also, x:

it will be evident that certain features of the invention have utility and advantages in situations other than that specifically mentioned herein. It is intended, therefore, that the foregoing description should be considered as exemplary only and the scope of the invention should be ascertained from the following claims.

I claim:

1. An attachment for the moldboard of a bulldozer, comprising a frame having a pair of laterally spaced uprights, means on said frame defining an upwardly opening notch for the reception of the lower end of said moldboard, a unitary clamp slidably mounted on said uprights and including a pair of laterally spaced gripping members for engaging the upper end of said moldboard, a single screw fixed to said frame and extending upwardly substantially parallel to said uprights through an opening in said clamp, a wing nut threaded on said screw above said clamp for urging said clamp downwardly to clamp said moldboard between said notch and said gripping members, and a blade on the lower end of said frame.

plate forming a plurality of upwardly opening laterally spaced notches for the reception of the lower end of the moldboard, a pair of spaced uprights rigid with respect to said backing plate and extending upwardly therefrom, a clamp slidably mounted on said uprights and including a pair of laterally spaced gripping members extending rearwardly therefrom, each of said gripping members being shaped so that its lower surface includes two angularly related planes for engaging respectively the front and rear edges of the upper end of the moldboard, an adjustment plate between and rigid with said uprights and having a group of vertically spaced holes therethrough, an inverted U-shaped member embracing the upper end of said adjustment plate and having a hole in each of its depending portions, a pin removably positioned in the holes in said U-shaped member and a selected one of the holes in said adjustment plate, an elongated screw rigid with the upper end of said U-shaped member and extending upwardly through an opening in said clamp, and a wing nut threadedly mounted upon the upper end of said screw in position to bear against the upper surface of said clamp and exert clamping pressure thereon.

3. A footing-trencher attachment for a moldboard of Y a bulldozer, comprising a generally rectangular trenchforming blade, a backing plate having said blade detachably secured to the front face thereof, means on the rear face of said backing plate forming therewith a plurality of upwardly opening laterally spaced notches for the reception of the lower edge of the moldboard, a pair of spaced uprights rigid with respect to said backing plate and extending upwardly therefrom, a clamp slidably mounted on said uprights and including a pair of laterally spaced gripping members extending rearwardly therefrom, each of said gripping members being shaped so that its lower surface includes two angularly related planes for engaging respectively the front and rear portions of the upper edge of the moldboard, and means for drawing said clamp downwardly to clamp said moldboard between said notches and gripping members.

4. A footing-trencher attachment for a moldboard of a bulldozer, comprising an upright frame, a trench-forming blade detachably secured to said frame, means on the rear of said frame forming a plurality of laterally spaced upwardly opening notches for the reception of the lower edge of the moldboard, a clamp slidably mounted on said frame, means for drawing said clamp downwardly to engage the upper edge of said moldboard comprising an adjustment plate rigid with said frame and having a group of vertically spaced holes therethrough, an inverted U-shaped member embracing the upper end of said adjustment plate and having a hole in each of its depending portions, a pin removably positioned in the holes in said U-shaped member and a selected one of the holes in said adjustment plate, an elongated screw rigid with the upper end of said U-shaped member and extending upwardly through an opening in said clamp, and a wing nut threadedly mounted upon the upper end of said screw in position to bear against the upper surface of said clamp and exert clamping pressure thereon.

References Cited in the file of this patent UNITED STATES PATENTS 2,536,308 

